1. Field of the Invention
The present invention relates to a wire guide nozzle which is usable for feeding a wire into a wire measuring apparatus in a manufacturing installation for producing wire harness to be arranged in e.g. an automobile. Further, the invention relates to a wire guide nozzle unit and an attachment and detachment mechanism for the wire guide nozzle.
2. Description of Related Art
Japanese Unexamined Patent Publication (kokai) No. 2-263533 discloses a conventional wire guide nozzle.
This wire guide nozzle assembly includes a first guide nozzle, a second guide nozzle on the front side of the first guide nozzle as a center and a third guide nozzle on the rear side of the first guide nozzle. The first guide nozzle is straight connected with the second guide nozzle through a connecting rod, while the first guide nozzle is straight connected with the third guide nozzle through another connecting rod. Provided between the first guide nozzle and the second guide nozzle is a wire holding section which includes a pair of opposing feed rollers. Also, another wire holding section having a plurality of calibration rollers is defined between the first guide nozzle and the third guide nozzle.
The first guide nozzle is provided with a wire pusher pin which penetrates the nozzle. The wire pusher pin has a wire through hole formed at the intermediate portion and a coil spring disposed on the base portion. When the wire guide nozzle assembly is not in use, an electrical wire inserted into the wire through-hole is urged against the inner wall of the nozzle by the wire pusher pin, in order to prevent the wire from being withdrawn from the wire through-hole. When the wire guide nozzle assembly is in use, that is, a pair of opposing feed rollers are closed to each other, then a release lever on the opposite side of the coil spring acts to press back a leading end of the wire pusher pin in opposition to the force of the coil spring, thereby allowing the wire to be fed. In this way, the wire is fed to a wire measuring apparatus.
Under condition that the first and third guide nozzles are fixed on profile members respectively fixed on two timing belts through bolts, a plurality of wire guide nozzles are arranged mounted in the longitudinal direction of the timing belts at regular intervals.
However, the above-mentioned wire guide nozzle assembly has the following problems to be solved due to the structure where three pieces of guide nozzles are assembled to each other through two connecting rods.
First, it should be noted that there is a difficulty of assembling three guide nozzles in a straight line. When the nozzles are not assembled in the straight line, then the rollers moving in the wire supporting area interfere with the guide nozzles, so that the guide nozzles may be damaged or the wire may be fed inappropriately.
Additionally, because of the structure composed of five components, there is a possibility that the components are mutually deviated from each other when a worker handles the wire guide nozzle. For this reason, the above-mentioned wire guide nozzle assembly has not been handled as a single unit and therefore, it has been used on condition that it is fixed to the above-mentioned timing belts. Under such a situation, it is impossible to apply so-called "outside setting" on the conventional wire guide nozzle assembly in advance. For example, when the wires have to be exchanged due to the required change in wire's color or diameter, the operation of machines (e.g. measuring apparatus) has to be stopped to withdraw or insert the wires. In such a case, the availability factor of the machine will be reduced. It should be noted that, under the reduced availability factor of the machine, the more the number of wires requiring to be exchanged is increased, the more seriously the productivity is influenced.